Mitsubishi Electric MELSEC FX3U Programming Manual page 122

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
2) When special analog adapters and FX
Counter type
Software
counter
C241,
C242, C235, C236,
C243, C237, C238,
1-phase
C244, C239, C240
1-counting input
C245
C244(OP),
−
C245(OP)
C247,
C248, C246,
1-phase
2-counting input C249, C248(OP)
C250
1 edge
2-
C252,
count
phase
C253(OP),
2-
C251, C253
count- C254,
4 edge
ing
count
C255
input
*1. When an index register is added to a counter number specified by a HSCS, HSCR, HSZ or HSCT
instruction, all hardware counters are switched to software counters.
*2. The high speed counters C244 (OP) and C245 (OP) can count up to 10 kHz.
3. Calculation of the total frequency
Total frequency ≥ Sum of "Response frequency of high speed counter ×
Magnification for calculating total frequency"
4. Calculation example
When only HSZ instruction is used 6 times in a program, the total frequency and response frequency are
calculated as follows in accordance with the columns for "When only HSZ instruction is used" shown above.
This calculation example is provided for a system configuration not including special analog adapters and
FX /FX Series special function blocks/units.
3U 3UC
Used high speed counter No.
C237
C241
C253(OP)
[4 edge count]
1) The total frequency is calculated as follows because HSZ instruction is used 6 times:
Total frequency
2) The sum of the response frequencies of the high speed counters
being used is calculated as follows:
"30 kHz × 1[C237]" + "20 kHz × 1[C241]" + "4kHz × 4[C253(OP)]" = 66 kHz ≤ 71 kHz
120
When HSZ and HSCT
Magnifica-
Following
instructions are not
tion for
software
calculating
counter with
total Maximum
HSCS, HSCR,
frequency response
HSZ or HSCT
frequency
instruction *1
(kHz)
×1
30
×1
10
×1
30
×1
30
×4
7.5
frequency
Operates as
software counter
Software counter
= 80 − 1.5 × 6 = 71 kHz
/FX Series special function blocks/units are used
3U 3UC
Response frequency and total frequency according to instruction use condition
When only HSCT
instruction is used
used
Maximum
Total
response
frequency frequency
frequency
(kHz)
(kHz)
25
10
60
25
25
6.2
Input Maximum response frequency
calculation
40 − 6 (times) = 34 kHz
30 kHz
40 − 6(times) = 34 kHz
20 kHz
{40 − 6(times)} ÷ 4 = 8.5 kHz
4 kHz
4.7 High Speed Counter [C] (FX3U/FX3UC PLC)
When only HSZ
instruction is used
Maximum
Total Total
response
frequency
frequency
(kHz) (kHz)
(kHz)
30 - (Num-
ber of
50−
instruc-
1.5×(Num
*2
tion)
50
ber of
instruc-
tion)
(30-Num-
ber of
instruc-
tion) ÷ 4
Magnification
for calculating
total frequency
× 1
× 1
× 4
4 Devices in Detail
When both HSZ and HSCT
instructions are used
Maximum
Total
response
frequency
frequency
(kHz)
(kHz)
25-(Number
of instruc-
50−
*2
tion)
1.5×(Num
ber of
instruc-
tion)
(25-Number
of instruction)
÷ 4
Used
instruction
HSZ
instruction × 6
times